The integration of an integrated circuit which is a main part of microelectronics has been increased year by year. With the increase of the integration, process technologies, which can provide a fine pattern on a substrate, such as fine etching technology and the like as well as a thin film deposition technology have been required. Under such requirements, various technologies of applying a halogen-containing gas have been put into practice.
In the etching, which is one of the process technologies, there exist various dry etching technologies for processing a semiconductive substrate or a thin film deposited on the substrate through the steps of using a halogen-containing gas under low pressure or high vacuum and exciting this halogen-containing gas by some means. As for this example, there has been known a process of exciting a halogen gas by exposing to plasma, or by the irradiation of an electron beam, an ion beam or a light. Especially, the etching by exposing to plasma has been widely applied since it is highly practicable. Recently, there have been put into practice high-density plasma etching technologies of applying ECR (Electron Cyclotron Resonance) type of plasma, ICP (Induction-Coupled Plasma), or a plasma method (hereinafter referred as to "UHF plasma") generated in the course of electric discharge caused by applying an electric field of high frequency ranging in VHF to UHF bands, that is, nearly from 100 to 1,000 MHz and the like in addition to parallel-plate type of plasma etching technology. In these etching technologies, using a halogen-containing gas such as fluorocarbon (CF.sub.4, C.sub.4 F.sub.8 and the like) makes it possible to etch a semiconductive material including silicon (Si) and the like, insulating material including silicon oxide (SiO.sub.2), silicon nitride (SiN) and the like, and a metallic material including aluminum and the like, or to remove selectively one of these materials by etching. Accordingly, this type of halogen-containing gas is indispensable for forming a fine pattern on the substrate.
In the process technologies other than the etching technology, for example, a thin film deposition technology, a halogen-containing gas also has been widely used as raw materials. As an example of this, a case of depositing a fluorinated amorphous carbon (a-C:F) film by applying a plasma CVD (Chemical Vapor Deposition by using plasma) process is given. As disclosed in Japanese Patent Kokai Publication Nos. JP-A-8-83842 (1996) and JP-A-8-222557 (1996), the a-C:F can be prepared by introducing a fluorocarbon gas such as CF.sub.4 and the like solely or together with a hydrocarbon gas such as CH.sub.4 and the like into plasma. Many type of plasma can be used in this process. The usable plasma includes parallel-plate type of plasma, ECR type of plasma, ICP, helicon type of plasma, UHF plasma and the like. As for other example, a case of depositing a titanium film by using TiCl.sub.4 a case of tungsten by using WF.sub.6 and the like are given.
In these processes of treating the substrate, the species which act on the substrate are not parent molecules of the gas themselves but the active species of radicals and/or ions resulting from the dissociation of these molecules by the action of plasma and the like.